Bone Abstracts

Background: Since Microcephalic osteoplasic dysplasia; Saul Wilson Syndrome (SWS) was first reported by Saul and Wilson in 1990 only 14 cases have been reported worldwide. In 2018 Ferreira et al identified the pathophysiological mechanism for SWS as a recurrent De Novo Heterozygous COG4 Substitution.

Objective: To describe the diagnostic process in a case of SWS.

Presenting problem: The patient is the first-born child of healthy, non-consanguineous parents. Pregnancy and delivery was normal with birth weight and length within normal limits for GA. After birth he presented with severe failure to thrive. His anterior fontanelle was large and extended to the dorsum nasi at birth. At 4 months he had an aventricular peritoneal shunt on clinical indication. He presented with dysmorphic craniofacial features: low set ears, small dysplastic face with micrognathia, and narrow nasal bridge, contractures of the elbow and knees, clubfoot and short distal phalanges. In the beginning his speech development was impaired. He is hearing impaired and ocular findings are blue sclerae, prominent eyes and cataracts. The MRI showed delayed myelination, hypoplasia of corpus callosum, small cysts in capsula interna and anterior displacement of atlas with abnormal course of the proximal cervical medulla and pons. The 3D CT of the cranium showed open sutures, delayed ossification and an abnormal spine with shortened vertebra and subluxation.

Clinical management: The patient had several investigations performed without finding the diagnosis: Array CGH, conventional chromosomes and X-ray of whole skeleton. At the age of three a splenectomy was performed due to an enlarged spleen, anaemia and thrombocytopenia. The patient is neutropenic and prone to infections. Due to two severe femur fractures treatment with bisphosphonate and zoledronic acid was initiated. The diagnosis was made, when the patient was 10 years old, after a photo of a patient with similar dysmorphic features was discovered and WES showed the patient to be heterozygous for c.1546G>A, p.Gly516Arg in the COG4-gene. The treatment of SWS is symptomatic and patients have lived in to adulthood.

Conclusion: This case shows how important collaboration between clinicians and scientists are in dealing with and diagnosing very rare cases of bone dysplasia.

Disclosure: The authors declared no competing interests.